Conventionally, resin beads have been used in various fields, such as a matting agent, a lubricant, and an antiblocking agent, because of the characteristics originating in the spherical shape. Furthermore, various kinds of resin powders (resin particles) have been used as makeup application in cosmetic materials in order to improve extensibility. However, these resin powders are liable to bleed due to water or sweat, thus there is a problem that makeup deterioration occurs when such bleed occurs, and when the resin powders are utilized in cosmetic materials, hydrophobization treatment has been applied to the surface of a powder in order to increase adhesion of the resin powder to skin and improve water repellency, or other purposes.
As the method of applying hydrophobization treatment to a powder, a method of applying heat treatment with an oil agent to the surface of a powder, a method of baking a methyl hydrogen polysiloxane onto a powder, and so on are known. Furthermore, there is a proposal on a powder the surface of which is coated with, for example, a silicone-acrylic-based graft copolymer in order to obtain a cosmetic material that achieves a higher functionality, that is excellent in adherence to skin and in feeling after use, that is rich in hydrophobicity, and that has a favorable persistence of makeup (see, Patent Literature 1).
Moreover, in Patent Literature 2, it is pointed out that, even though imparting water repellency, improving adherence to skin or the like, and securing compatibility with a coexisting oil agent are simultaneously required for silicone polymers that are often used in cosmetic materials, hydrophilicity is lost by introducing a long-chain alkyl group (hydrophobic group) in a silicone polymer in order to improve compatibility and on the other hand, hydrophobicity is lost by introducing a hydrophilic group in order to improve adherence, and thus it is difficult to solve the compatibility and the adherence simultaneously. Against the problem, there is a proposal on a copolymer obtained by copolymerizing four kinds of different monomer units each containing a particular amount of a silicone macromonomer having a particular structure.